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Pacific Southwest, Region 9

Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations

PM-10 Federal Implementation Plan for the Maricopa County Area

NOTE: This content is no longer being updated. The most up to date information can be found in Federal Register Notices and Approved Air Quality Implementation Plans in Region 9.

Executive Summary


The Phoenix area violates both the annual and 24-hour national health-based standards for particulate matter with diameters of 10 microns or less (PM-10). Consequently, Maricopa County residents continue to breathe unhealthy air. Particulate matter affects the respiratory system and can cause damage to lung tissue and premature death. The elderly, children, and people with chronic lung disease, influenza, or asthma are especially sensitive to high levels of particulate matter. EPA has established a new standard for particulate matter with diameters of 2.5 microns or less and revised the PM-10 standards. However, EPA also retained the pre-existing PM-10 standards for a limited amount of time. The FIP only addresses those pre-existing PM-10 standards.

The primary cause of the PM-10 problem in the Phoenix area is dust on paved roads kicked up by vehicle traffic, and windblown dust from construction sites, earth moving operations, unpaved parking lots and roads, disturbed vacant lots, agricultural fields and aprons, and other disturbed areas.

When an area violates a health-based standard, the Clean air Act (CAA) requires that the area be designated as nonattainment for that pollutant. Phoenix was originally designated and classified as a moderate nonattainment area for particulate matter, and Arizona was required to develop a plan that put into place a basic set of control measures. These measures did not adequately control the particulate pollution problem. When the area failed to attain the standards in 1994 it was reclassified as a serious nonattainment area, and the State is now required to develop a plan with more comprehensive control measures.

Despite the fact that the State is now working on its serious area plan, EPA is under court order, as a result of a lawsuit by the Arizona Center for Law in the Public Interest (ACLPI), to develop a moderate area federal implementation plan (FIP) for the Maricopa area. EPA is required to prepare this FIP because the State does not have an approved moderate area plan. Under the court order, EPA was required to issue the FIP by July 18, 1998.

In its FIP proposal (63 FR 15920; April 1, 1998), EPA determined that not all the basic controls on sources contributing to violations of the particulate standards were in place. While the State had implemented a number of measures, including controls on construction and earth moving operations, there remained a need for additional emissions reductions. Having considered its authority and resource constraints, EPA proposed two measures in that rulemaking for the control of dust from unpaved roads, parking lots, and vacant lots and agricultural fields and aprons. Specifically, EPA proposed a fugitive dust rule and an enforceable commitment in regulatory form to implement control measures for agricultural PM-10 sources by June 2000. These measures will contribute to the eventual attainment of both the annual and 24-hour PM-10 standards. EPA received comments from the public on the FIP proposal and has made changes to the proposed FIP rule for fugitive dust sources which it is finalizing today.

The State intended to submit its serious area particulate plan in December of 1998. If the plan includes control measures for the sources covered by the FIP and those measures are approved by EPA, the Agency will be able to withdraw the final FIP measures. EPA will continue working with the appropriate State and local agencies, as well as the agricultural community and the cities in the metropolitan area, to replace the FIP measures with State measures. EPA believes that clean air is likely to be achieved faster, and in greater harmony with local economic and community goals, if its role as a backstop is minimized by effective State and local actions. Because of the willingness of the State and local communities to identify and pursue solutions to their air quality problems, as evidenced by the Governor's air Quality Strategies Task Force and the recently adopted air Quality Measures Bill (SB 1427), EPA expects successful State and local action.

Public involvement in the FIP process

On April 16, 1998, EPA held a workshop and public hearing on its proposal in Phoenix. The workshop provided an opportunity for EPA to explain to the community why the Agency is imposing this FIP, what measures are included in the FIP, and who will potentially be impacted by the FIP. The workshop also provided the community the opportunity to ask questions of EPA, and to make suggestions with respect to its proposed action. Following the workshop, EPA took formal testimony at a public hearing on the FIP proposal. In addition to the hearing testimony, EPA received 18 comment letters on the proposed FIP.

The comments generally fell into two categories. Environmental and health organizations supported the dust rule, but felt that the FIP did not impose PM-10 controls for other categories in the Phoenix PM-10 nonattainment area. On the other hand, several of the local jurisdictions and regulatory agencies felt that the FIP imposed controls that were too stringent. EPA evaluated all the comments, did additional fieldwork and technical anlaysis, and revised the FIP accordingly.

Summary of the FIP

In response to public comments, EPA revised the fugitive dust rule, but did not change the enforceable commitment for agriculture.

Fugitive Dust Rule

Although EPA has approved a Maricopa County rule (MCESD Rule 310) which requires controls for unpaved roads, unpaved parking lots and vacant lots, the County is not adequately enforcing its rule for these three sources due to lack of resources. Consequently, EPA promulgated a FIP rule for these sources. EPA's fugitive dust rule is intended to establish basic levels of control that are substantially equivalent to those established by Maricopa County Rule 310. The primary difference between the FIP rule and Rule 310 is the greater specificity and detail regarding which control measures are appropriate for which sources. For each source category, the FIP rule includes three to four control measure options and allows alternative control measures.

In order to effectively implement the FIP rule, EPA is providing additional inspection resources to the Maricopa County Environmental Services Department (MCESD) through a CAA section 105 grant. EPA will rely on these resources to assist the Agency in verifying compliance with the FIP rule. In order to remove the FIP requirement, MCESD will have to submit to EPA a credible implementation strategy for Rule 310, including the provision of its own additional inspection and enforcement resources that are not provided under an EPA grant. It is EPA's understanding that MCESD is trying to obtain these additional resources. EPA will continue working with the County to assist that effort so that the FIP rule can eventually be rescinded.

Until the FIP is rescinded, however, EPA intends to work cooperatively with MCESD to inform the regulated community of the FIP rule's requirements. EPA plans to provide compliance assistance through informational brochures, toll free numbers and internet access. These tools will help EPA disseminate as much information as possible to the public. As new information becomes available, including alternative control measures that are being developed by regulated parties to comply with the rule, EPA will collaboratively work with these regulated parties to provide information to the public.

EPA would like to clarify the Agency's position with respect to a major issue that was raised by several commenters on the proposed fugitive dust rule. These commenters believe that the FIP rule requires a more stringent level of control than Maricopa County Rule 310 and that, consequently, EPA is imposing an additional economic burden on local municipalities, and others impacted by the FIP rule. EPA believes that the FIP rule does not impose any additional compliance burden beyond that required by Rule 310. Because EPA will fully enforce the FIP rule, which has not occurred under Rule 310, regulated entities who have not been in compliance with existing requirements to date will need to spend the resources necessary to come into compliance. This is not an additional economic burden, but rather one that some members of the regulated community have deferred. However, should EPA receive new information in the future that indicates that the FIP controls are more stringent than those required by the Clean air Act, the Agency will propose appropriate revisions to the FIP.

Enforceable Commitment for Agriculture

As mentioned above, EPA has approved Maricopa County Rule 310 which requires control of fugitive dust sources, including agricultural sources. However, MCESD is not ensuring adequate enforcement of the rule for agricultural fields and aprons. Therefore, EPA promulgated an enforceable commitment in regulatory form for the FIP that required EPA to propose controls on agricultural sources by September 1999 and implement these controls by June 2000. The enforceable commitment has not changed from the April 1, 1998 proposal. In discussions with key stakeholders, general agreement was reached that these controls will be in the form of best management practices. EPA believes that this approach will ensure successful dust control in Maricopa's unique environment. We have worked closely with the Phoenix farming community to develop this commitment, and their comments on the proposal support it.

In order to remove the FIP requirements, the State will need to submit and receive approval of a SIP measure that replaces the enforceable commitment. In fact, the Arizona legislature has passed, and Governor Hull has signed, the legislative language needed to establish a state process to develop best management practices for control of PM-10. EPA expects to receive this legislative language as a SIP revision very shortly and will act on it expeditiously.

Tribal Issues

There are three Indian reservations located within the Phoenix nonattainment area. However, since this FIP is designed to fill a gap that exists in the State plan which does not apply to sources within Indian country, EPA has not included Indian reservations in this FIP. All three tribes have expressed an interest in developing air quality programs. EPA will develop the data, in cooperation with the tribes, that is needed to properly assess whether controls are required to attain the standards. EPA will ensure that controls are implemented either through EPA-approved tribal measures or, if necessary, federal measures.


EPA appreciates the comments that were made on the proposed FIP and will continue to work with the community as the Agency moves forward to implement the FIP measures. EPA will also continue to work with the community on the development of the State's serious area plan. EPA is hopeful that the local planning effort will result in an approvable SIP that will allow EPA to withdraw its FIP.

For more information:

Please contact Colleen McKaughan, Associate Director, air Division, U.S. EPA Region 9 at (520) 498-0118. Send questions and comments tor9.phoenixdust@epa.gov

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